The opponents in this case, she says, are New York Mayor Michael Bloomberg and President Barack Obama. The mayor, co-founder of Bloomberg LP, parent company of Bloomberg News, is among the mayors in Mayors Against Illegal Guns who announced a new TV ad this week targeting Ayotte for her vote against the background check bill that died in the Senate for lack of 60 votes.

In doing so, the mayors say, Ayotte voted against the 89 percent of New Hampshire voters who support the measure. Ayotte has been singled out more than any of the other Republican opponents of the measure because of where she lives, a swing state that is sympathetic to Democratic causes.

Ayotte says the legislation she opposed, which would require purchasers at gun shows and over the Internet to undergo the same criminal background checks as those buying weapons from licensed firearm dealers, would do “nothing to prevent a deranged individual from obtaining and misusing firearms to commit horrific tragedies like the one in Newtown.”

The mayors’ ad, called “Gone Washington,” is airing in Manchester, N.H., and Boston markets in rotation with another ad featuring testimonials from Granite Staters who support the legislation. “Why didn’t she listen to us in New Hampshire?” a woman asks in the ad. Another says, in closing: “New Hampshire voters will remember this.”

In a fundraising email appeal to supporters today, Ayotte complained that Bloomberg and Obama “want to take me out.”

“But Mayor Bloomberg and Harry Reid can’t bully me into changing my vote, because this legislation would have gone too far in restricting the Constitutional rights of law-abiding gun owners, while doing nothing to prevent a deranged individual or criminal from obtaining and misusing firearms to commit horrific tragedies like the one in Newtown,” Ayotte writes in her appeal for money to “fight back.”

Ayotte is getting some defensive coverage from the National Rifle Association in its own radio and TV ads in New Hampshire.

“Don’t believe” the ads by the mayors, the NRA’s ad for Ayotte says, singling out Bloomberg. “Kelly Ayotte stands with New Hampshire prosecutors and police for New Hampshire values.”